What Happens When Non-equal Voltages Are Put in Parallel? [duplicate]

What happens when non-equal voltages are put in parallel? [duplicate]

Firstly, I am assuming these batteries to be DC, otherwise this solution is wrong:If you connect multiple batteries to a circuit, their polarity makes all the difference. If they are opposite in polarity then the battery with lower voltage will charge. A diagram will help to elaborate the question if you are talking about a specific arrangement. If the batteries are of same polarity, then neither will charge. The detailed solution can be attempted by Kirchoff's loop and junction law. These laws are helpful in parallel connections mainly. ..Hope it helps!.

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What's with the operating voltages: 5V, 3.3V, 2.5V, 1.8V, etc

"Why do smaller devices require lower voltages?" Smaller ICs have less surface to get rid of the heat. Whenever a bit toggles somewhere in an IC, a capacitor has to be charged or discharged (i.e. the gate capacitance of a CMOS transistor). Although the transisotrs in a digital IC are usually very very tiny, there are a lot of them, so the issue is still important. The energy stored in a capacitor is equal to 0.5*C*U^2. Twice the voltage will cause 2^2=4 times the energy that has to be used for every MOSFET's gate. Therefore, even a small step down from, say, 2.5V to 1.8V will bring a considerabe improvement. That's why IC designers did not just stick to 5V for decades and waited until the technology was ready to use 1.2V, but used all the other funny voltage levels in between.

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For analog summing and multiplying, what would be the disadvantages of scaling down voltages of input?

There is no particular serious problem with this approach. The inputs do not need to stay within the supply voltage range if the series resistors are high enough (though you do need to worry about what may happen if the input is connected to an external voltage and there is no supply voltage- the summing junction will no longer be at virtual ground and current will flow somewhere). You can calculate the voltage and current noise as usual, high value resistors will have greater Johnson-Nyquist noise, and the noise current of the amplifier will have more influence, but neither is normally much of an issue. It may be necessary to add some capacitors in the resistor ratio if you have very high value resistors (to get flatter AC response, increase stability and decrease noise)

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Electrical grid based on devices in series using constant currents, not devices in parallel using constant voltages

Wo not work.Losses inside a conductor are proportional to R * I^2.Therefore, all other things being equal (insulation melting temperature, etc) the conductor cross-section which determines R has to be inversely proportional to I^2.Problem #1: If your house had a "120A" circuit instead of "120V" then all wires would have to be rated for 120A, which would make them impractically large and expensive. In fact, everything would have to be rated for this, even the switches, lampcord, etc.Here (France) the average wall socket allows 230V/16A (ie, 3500W nominal). So let's keep the wires rated at 16A, and the constant current supply at 16A too. If the house draws 10kW maximum, then it will have 625V across its supply. Manageable.However, it is in series with the neighbor's houses unless the utility provides a transformer winding for each subscriber. Since voltages add up, the wiring will be at potentially several kV relative to Protection Earth. Therefore:Problem #2: Unsafe voltages. Problem #3: Three phase induction motors would be a problem. This means no industry.Problem #4: The efficiency for low loads would be catastrophic. Say a cellphone charger, drawing 5W = 0. The losses in wiring would no longer be insignificant relative to delivered power.

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What are the sources of over voltages in power system?

Lightning and switching over voltages which are transient in nature but of large magnitude.In addition, Temporary over voltages are of less magnitude but longer duration and are due tomalfunctioning of voltage regulators,sudden loss of large load in the system,single line to ground (SLG) faults causing voltage rise of healthy phases andneutral circuit fault in case of 415V distribution systems

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Why are transmission voltages 400 kV, 230 kV, and 132 kV? Why not 410 kV, 220 kV, and 150 kV?

These voltages are due to a common agreement in the industry, which is then captured in standards like IEEE or IEC. If you had a new agreement on other numbers and equipment would be designed to that, it would work just as well